Dispersion Compensation in Non-Linear Self Phase Modulation (SPM) and Cross Phase Modulation (XPM) Induced Optical Channel Using Vectorial MLSE Equalizer

We propose and experimentally demonstrate an improved vectorial maximum likelihood sequence equalizer (MLSE) method that enhances inter-symbol-interference (ISI) mitigation in highly non-linearly distorted channel by self phase modulation (SPM) in a single channel system and cross phase modulation (XPM) in WDM system. The vectorial MLSE is based on "over sampling" of the distorted signal according to Nyquist criterion of the broadened signal spectrum due to SPM. For XPM, the noise caused by this effect is modeled using histogram estimation with multiple samples per bit. Experimental and computer simulation results indicate significant improvement of BER results using the proposed vectorial equalizer.